Objective To clarify relationship between signal heterogeneity on hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI and prognosis of hepatocellular carcinoma (HCC). Methods From January 2014 to January 2017 in the First Affiliated Hospital of Chongqing Medical University, a total of 77 patients with the pathologically proved HCC underwent Gd-EOB-DTPA-enhanced MRI prior to surgery were included in this study. On the basis of the signal heterogeneity in the hepatobiliary phase, the included patients were designed to homogeneous hypointensity group and heterogeneous hyperintensity group. The disease-free survival time were compared between the 2 groups and it’s influencing factors were analyzed. Results Seventy-seven patients with HCC were included, including 45 cases of homogeneous hypointensity and 32 cases of heterogeneous hyperintensity. There were no significant differences in the age, gender, etiology, liver function, alpha-fetoprotein, differentiated degree, Child-Pugh grade, lesion diameter, lesion border, and number of lesions between the 2 groups (P>0.05). However, the HCC patients with heterogeneous hyperintensity had a later BCLC staging (P=0.001). The disease-free survival time of the patients with homogeneous hypointensity and heterogeneous hyperintensity was (17.0±9.8) months and (12.4±10.4)months, respectively. The Kaplan-Meier survival curve showed that the disease-free survival time in the patients with homogeneous hypointensity was significantly better than that in the patients with heterogeneous hyperintensity (P=0.020). The results of univariate analysis showed that the other confounding factors had no effect on the disease-free survival time of patients with hepatocellular carcinoma (P>0.05) except for the signal of hepatobiliary phase (P<0.05). Furthermore, the hepatobiliary phase signal, BCLC stage, and degree of differentiation, which might be clinically considered as potentially influencing for the prognosis of patients with HCC, were included in the Cox multivariate proportional hazard regression model and found that the heterogeneous hyperintensity was still the risk factor of the disease-free survival rate in patients with HCC (P=0.047). Conclusion Signal heterogeneity on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI is related to prognosis of patients with HCC, heterogeneous hyperintensity may indicate a lower disease-free survival rate.
ObjectiveTo summarize the application of magnetic resonance imaging (MRI) in the evaluation of pancreatic exocrine function.MethodIn this paper, we reviewed and summarized the related literatures about the application of MRI in the field of pancreatic exocrine function evaluation in recent years.ResultsA variety of MRI techniques could be used to detect the pancreatic exocrine function. In addition to conventional MRI techniques, there were also MRI stimulated by pancreatic secretions, cine (dynamic) cholangiopancreatography based on space selective reverse recovery pulse, and so on.ConclusionThe new MRI techniques have potential for semi-quantitative and quantitative evaluation of pancreatic exocrine function.
Objective To evaluate the imaging features of hepatic epithelioid hemangioendothelioma (HEHE). Methods The imaging data of 15 patients with HEHE proved by surgery and pathology who reeived treatment in West China Hospital from Jul. 2012 to Aug. 2018, were retrospectively analyzed. The location, boundary, density/signal, and enhanced features of tumor were observed. Results Among 15 cases, there were 3 cases of single, 5 cases of multiple, and 6 cases of fusion. Thirteen cases were distributed under the capsular of liver, accompanied by the capsule retraction sign, 14 cases had lollipop sign, 7 cases had core pattern sign. On plain CT images, the lesions manifested as low density. On plain MR images, the lesions had hypointense on T1-weighted images and hyperintense on T2-weighted images. The enhanced scanning could be characterized by mild enhancement, rim-like enhancement at early phase, and progressive centripetal fill-in enhancement during dynamic phase imaging. Conclusions CT and MRI imagings of HEHE are different, and there are certain characteristics of capsule retraction sign, lollipop sign, and core pattern sign.
Pulsed magnetic field gradients generated by gradient coils are widely used in signal location in magnetic resonance imaging (MRI). However, gradient coils can also induce eddy currents in final magnetic field in the nearby conducting structures which lead to distortion and artifact in images, misguiding clinical diagnosis. We tried in our laboratory to measure the magnetic field of gradient-induced eddy current in 1.5 T superconducting magnetic resonance imaging device; and extracted key parameters including amplitude and time constant of exponential terms according to inductance-resistance series mathematical module. These parameters of both self-induced component and crossing component are useful to design digital filters to implement pulse pre-emphasize to reshape the waveform. A measure device that is a basement equipped with phantoms and receiving coils was designed and placed in the isocenter of the magnetic field. By applying testing sequence, contrast experiments were carried out in a superconducting magnet before and after eddy current compensation. Sets of one dimension signal were obtained as raw data to calculate gradient-induced eddy currents. Curve fitting by least squares method was also done to match inductance-resistance series module. The results also illustrated that pulse pre-emphasize measurement with digital filter was correct and effective in reducing eddy current effect. Pre-emphasize waveform was developed based on system function. The usefulness of pre-emphasize measurement in reducing eddy current was confirmed and the improvement was also presented. All these are valuable for reducing artifact in magnetic resonance imaging device.
To solve the problem of precise positioning of carp brain tissue coordinates, it is proposed in this paper for a method for transforming the coordinates of magnetic resonance imaging of carp brain tissue into the coordinates of electrode implantation using a brain stereotaxic apparatus. In this study, the 3.0T magnetic resonance imaging instrument was used to scan the carp brain. We independently established the three-dimensional positioning coordinate system of the brain, the three-dimensional coordinate assistance system of skull surface and the three-dimensional coordinate assistance system in brain tissue. After two coordinate transformations, the magnetic resonance image coordinates of the brain electrodes implantation sites were converted into the three-dimensional stereotactic coordinate system to guide the electrodes implantation. The experimental groups were divided into two groups, A and B. Group A was the group of magnetic resonance imaging apparatus combining with the brain stereotaxic apparatus, and group B was the group of brain atlas combining with the brain stereotaxic apparatus. Each group had 20 tails of carps (n = 20). This two methods were used to implant the electrodes into the cerebellar motor area. The underwater experiments of the carp robots were carried out to test the two methods. The results showed that the accuracy of the implanted electrodes were 90% in group A and 60% in group B. The success rate of group A was significantly higher than that of group B (P < 0.05). Therefore, the new method in this paper can accurately determine the coordinates of carp brain tissue.
ObjectiveTo help junior radiologists and surgeons better interpret MRI images of rectal cancer.MethodThe guidelines, expert consensus and research progress on the application of MR imaging in rectal cancer in recent years were reviewed.ResultsRectal MR had the ability to accurately evaluate a number of important findings that may impact patient’ management, including distance of the tumor to the mesorectal fascia, presence of extramural vascular invasion, and presence of lymph nodes.ConclusionsRectal MRI is an important basis for clinical staging and multidisciplinary diagnosis and treatment of rectal cancer. Surgeons and radiologists must master the key imaging anatomical basis and clinical practice points in order to accurately interpret the image information of MRI in rectal cancer.
Objective To summarize the CT, MRI, and positron emission computed tomography (PET) imaging findings of hematologic malignancies of the pancreas, so as to improve the capacity of its diagnosis. Methods After searching articles concerning radiological research about hematologic malignancies of the pancreas, summarizing its imaging characteristics. Results Hematologic malignancies of the pancreas include pancreatic lymphoma, pancreatic multiple myeloma, myeloid sarcoma, posttransplantation lymphoproliferative disorder, and giant lymph node hyperplasia. ① Pancreatic lymphoma: imaging features of pancreatic lymphoma are segmental or diffuse homogeneous enlargement of the pancreas, diameter of mass >5 cm, adenopathy below the level of renal veins, and lack of pancreatic duct dilation. Blurred margins of pancreas by lymphadenopathy is highly suggestive of lymphoma. ② Pancreatic multiple myeloma: pancreatic multiple myeloma are hyperintense on both T1- and T2-weighted images. ③ Pancreatic granulocytic sarcoma: pancreatic granulocytic sarcoma present as homogeneous hypoenhancing mass on CT, usually without pancreatic duct dilation. On MRI, the lesions are isointense and mildly hyperintense on T1- and T2-weighted images respectively. ④ Posttransplantation lymphoproliferative disorder: diameter of leison of posttransplantation lymphoproliferative disorder usually is >5 cm with poor enhancement. Lesions are mildly hyperintense on T2-weighted images and extremely hypermetabolic on PET images. ⑤ Giant lymph node hyperplasia: it mainly appear as solitary noninvasive masses. Punctate calcification and surrounding supply vessels are observed in hyaline vascular type. Plasma cell type demonstrate unapparent enhancement and less calcification. Conclusions Hematologic malignancies of the pancreas manifest different imaging features on CT, MRI, and PET. Familiarity with such characteristics helps to early recognize diseases and determine next-step measures.
ObjectiveTo explore the application value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) quantitative parameters and apparent diffusion coefficient (ADC) value in evaluating the differentiation degrees and T stages of rectal cancer.MethodsThe patients with rectal cancer from November 2017 to November 2019 in the Sichuan Provincial People’s Hospital were collected. The volume transfer constant (Ktrans), flux rate constant (Kep), and extravascular extracellular volume fraction (Ve), and ADC values of the tumors were measured and compared in the patients with the different differentiation degrees and T stages. The receiver operating characteristic (ROC) curve analysis was performed.ResultsAll of 53 eligible patients were included, including 13 cases of high differentiation, 30 cases of medium differentiation, and 10 cases of low differentiation; 5 cases of T1 stage, 8 cases of T2 stage, 24 cases of T3 stage, and 16 cases of T4 stage. ① There were statistical differences in the Ktrans and ADC values among the different differentiation degrees of rectal cancer (P=0.004, P<0.001), and no statistical differences in the Kep and Ve values (P>0.050) among them. The Ktrans value was increased with decreased differentiation degree (P<0.050), the ADC value was decreased with decreased differentiation degrees (P<0.050). ② There were statistical differences in the Ktrans and ADC values among the different T stages of rectal cancer (P=0.002; P=0.007), and no statistical differences in the Kep and Ve values (P>0.050) among them. The Ktrans and ADC values were statistically different between the T2 and T3 stages of rectal cancer (P=0.009, P=0.013). ③ The Ktrans and ADC values could distinguish the high and medium differentiation degrees of rectal cancer, its area under ROC curve (AUC) values were 0.677 and 0.763, respectively, and the corresponding best thresholds were 0.180/min and 1.179 mm2/s; The Ktrans and ADC values could distinguish the medium and low differentiation degrees of rectal cancer, its AUC values were 0.693 and 0.967, and the corresponding best thresholds were 0.281/min and 0.906 mm2/s; The Ktrans and ADC values could distinguish the T2 and T3 stages of rectal cancer, its AUC values were 0.862 and 0.742, and the corresponding best thresholds were 0.204/min and 1.579 mm2/s.ConclusionDCE-MRI quantitative parameters and ADC value before surgery to determine the different differentiation degrees and T stages of rectal cancer have certain reference value, the best Ktrans and ADC thresholds to distinguish different differentiation degrees and T2 to T3 stages can be obtained through statistical analysis.
The effect of deep brain stimulation (DBS) surgery treatment for Parkinson's disease is determined by the accuracy of the electrodes placement and localization. The subthalamic nuclei (STN) as the implant target is small and has no clear boundary on the images. In addition, the intra-operative magnetic resonance images (MRI) have such a low resolution that the artifacts of the electrodes impact the observation. The three-dimensional (3D) visualization of STN and other nuclei nearby is able to provide the surgeons with direct and accurate localizing information. In this study, pre- and intra-operative MRIs of the Parkinson's disease patients were used to realize the 3D visualization. After making a co-registration between the high-resolution pre-operative MRIs and the low-resolution intra-operative MRIs, we normalized the MRIs into a standard atlas space. We used a special threshold mask to search the lead trajectories in each axial slice. After checking the location of the electrode contacts with the coronal MRIs of the patients, we reconstructed the whole lead trajectories. Then the STN and other nuclei nearby in the standard atlas space were visualized with the grey images of the standard atlas, accomplishing the lead reconstruction and nerve nuclei visualization near STN of all patients. This study provides intuitive and quantitative information to identify the accuracy of the DBS electrode implantation, which could help decide the post-operative programming setting.
ObjectiveTo summarize the value of imaging in the evaluation of non-surgical therapy for pancreatic cancer.MethodThe relevant literatures about imaging evaluation of non-surgical therapy for pancreatic cancer were collected to make an review.ResultsAt present, most of the imaging evaluation of non-surgical therapy for pancreatic cancer were based on the assessment of morphological characteristics of tumors, such as contrast-enhanced CT and MRI. However, only morphological changes of tumors could not accurately evaluate the response of pancreatic cancer after non-surgical treatment. A few studies had explored the value of functional imaging and artificial intelligence.ConclusionsNon-surgical therapy provides new treatment opportunities for unresectable pancreatic cancer, especially the proposed of neoadjuvant therapy, which provides the possibility of operation for patients with advanced pancreatic cancer. More imaging indicators with stronger objectivity, higher accuracy, and wider universality need to be improved and developed in the future.